Boring bar



July 14, 1931.

F. S. HARTWELL BORING BAR Filed Aug. 23, 1926 2 Sheets-Sheet 1 QU i H wiwi-Emmi@ EW N Il 5322i@ July 14, 1931. F. s. HARTwELL BORING BAR 2 .Sheets-Sheet 2 Filed Aug. 23, 1926 atboz vw@ zuY Patented July 14, 1931 NETE!) vSTATES PATENT OFFICE FLOYD S. HARTWELL, OF CLEVELAND, OHIO., ASSIG-NOR T0 KELLY BEAMER COMPANY, OF CLEVELAND, OI-IIO BORING BAR Application led August 23, 1926. Serial No. 131,031.

This invention relates to boring bars and other rotary cutters.

Briefly stated, an important object is to provide a` boring bar in which the arrangement of the blades and the 'holding and adjusting means therefor is such that a substantial reduction in the size oi' the opening or openings for the reception of these parts is made possible whereby the strength of the barvadjacent thecutting units thereof `compares favorably with the strength of the bar elsewhere.

yA. further and equally important object is to provide a boring bar in which `the assembly and maintenance of the cutting and adjustingddevices is greatly simplified and cheapene Other objects and advantages will be apparent during the course of the following description.

Inthe accompanying drawings forming a part of this application and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a fragmentary side elevation ot a boring bar constructed in accordance with the invention;

Figure 2 isa longitudinal sectional view through the same;

vFigure 3 is a perspective of an adjusting and holding nut `embodied in the invention;

Figure 4 isa sectional view taken on line 4 4 of Figure2;

Figure 5 is an end elevation of a carrier embodied in the invention;

Figure 6 is a longitudinal sectional view through the carrier;

VFigure 7 is a sectional view taken on line i 7 7 of Figure 6;

Y Figure 8 is a group perspective of the carrier and associated elements.

In the drawings, wherein for the purpose of illustration is shown a preferredembodiment of theinvention, the numeral 5 designates a bar which may, of course, be provided vvith a shank 6 of any conventional or special design and by which the bar may 'be attached to a machine. y

The boring bar illustrated is especially adapted. for car wheel werk ands provided.

with longitudinally spacedL roughing, 'nishing and chamfering cutters. `The chamfering cutter is designated by the numeral 7. The

genera-l arrangement of the cutters, as illusat 10, lfor the reception of suitably stout radial lugs 11 on adjusting and holding sleeve nuts12.

In carrying out the invention, the sleeve nuts 12 are oppositely threaded and are mounted on the oppositely threaded portions of an adjusting and holding screwvl, the terminals of which are reduced and are eX- tended through holding plates 18. The holding plates may in turn be secured in the recessed ends ofa rectangular carrier 20, as

clearly suggested in Figures 2 and 8. The reduced end portions of the adjusting and holding screw 15 may be provided with heX- agonal sockets for the reception of an Allen wrench. Of course, the reduced end portions ot the screw 15 may be provided with `screw driver grooves or other tool engaging l means. v

Referring now to Figures 6 and 8, it will be seen that the carrier 20 is provided with a longitudinal channel interrupted 'intermediate the ends thereof by an arcuate bridge 22 upon which the reduced intermediate portion 240i the adjusting screw 15 rests. AIn other words, the reduced intermediate portion 24 of the screw 15 defines a pair of annular shoulders which, as clearly shown in Figurey 2, are engaged with opposite sides of the arcuate bridge 22 so that endwise movement of the kadjusting screw is positively prevented.

Particular attention is invited to the fact that the longitudinal channel in the carrier 2Q describes more than a semtcrcle and that narrow opening 9 in the bar.

the Hat, oppositely located side walls 26 of the carrier are engaged with the opposed edges of the radial lugs 11 to securely hold the sleeve nuts 12 against turning during the adjustment of the screw 15 or at any other time. Also, the sleeve nuts 12 are of a crosssectional diameter to snugly it within the longitudinal channel in the carrier 12 s0 that once the nuts 12 are mounted on the screw 15 and received in the channel the same will not get out of place. This greatly simplifies ythe same resting on the arcuate bridge 22.

It is important to note that when the screw 15 is originally7 introduced into the channel in the carrier it is not connected to and does not carry the sleeve nuts 12.

The sleeve nuts 12 are arranged on the ends of the screw 15 subsequent to the introduction of the screw into the channel of the carrier. rl`his is necessary because of the cross-sectional formation of the channel in the carrier. To move the sleeve nuts 12 to the desired places on the screws 15 it is merely necessary to turn the screw so as to move the sleeve nuts inwardly toward each other. Of course, it is desirable to start the sleeve nuts 12 onto the screw 15 at exactly the same time; otherwise they would not occupy the same Vrelative positions on the screw.

lVhen the sleeve nuts have thus been applied to the screw 15, the end plates 18 are secured byV screw bolts or other suitable fastening means to the ends of the carrier so as to brace the ends of the screw. rl"he blades 8 are now engaged with the radial lugs 11 and the parts thus assembled are introduced into the rather Finally, the taper screws are applied and tightened to firmly bind the blades and the holding means therefor in place against the strain to which the same will be subjected.v After the tightening of the taper screws 33, necessary adjustment of the bar tothe desired cutting diameter may be easily made by turning the screw 15 from either end thereof.

1t will be seen that the holding and aldj usting members are no wider than the width of the blades 8 as shown in Figure 7 and that these parts are arranged directly behind the blades so that the cross-sectional area of the opening or openings 9, as the case may be, may be such that the strength of thebar at the cutters compares favorably'withth'e strength of the bar elsewhere.

To provide a bar which is not substantially weakened at the cutters thereof is especially advantageous in a heavy duty boring bar of the type illustrated since the strain incident to the use of the roughing cutters must be borne by that part of the bar near the finishing cutters as well as other parts of the bar. In other words, the strain on that portion of the bar adjacent the finishing cutters is not materially less than the strain on the bar elsewhere.

Having thus described the invention, what is claimed:

1. A boring bar comprising a body having an opening of substantially the same width throughout, a cutter in said opening, a carrier within said opening and having a channel, the intermediate portion of which has a bridge, an adjusting screw having shoulders engaged with said bridge, nuts on said screw, and cutters having connection with said nuts,

' the carrier having a longitudinal groove the side walls of which are undercut, the nuts having enlarged body portions received in said groove whereby the undercut groove walls hold the nuts in place, lugs extending from the nuts to engage the cutter, said carrier being wholly at one side of the cutters, the latter having recesses to receive said lugs, the recesses being deeper than theprojective length of the lugs, and means for wedging said carrier against one edge of said cutters whereby to force the same against the opposite Wall of said opening, said carrier having the side edges thereof bearing directly against said cutters.

2. A boring bar comprising a body having an opening ofrsubstantially the same width throughout, a cutter in said opening, a carrier in said opening and having a channel opening out through one side thereof and having a wall describing more than a semi-"' circle, an adjusting screw havingoppositely threaded portions in said channel, nuts on said oppositely threaded portions and having sliding engagement with the channel. wall and being provided with lugs Vextending through said opening in the carrier, blades engaged by said lugs, sai-d carrier being provided with a bridge extending across said channel and engaging said screw to hold the screw against endwise movement, end plates an opening, la carrier in said opening and having ajchannel opening out through one side thereof and having a wall describing more than a semi-circle, an adjusting screw having oppositely threaded portions in said channel, nuts on said oppositely threaded portions and having sliding engagement With the channel Wall and being provided with lugs extending through said channel in the carrier, blades engaged by said lugs, said carrier being provided With a bridge extending across said channel and engaging said screw to hold the screw against endwise movement, end plates connected to said carrier and having openings receiving the end portions of said screw7 and looking means to hold said carrier in place, said carrier being located entirely at the edges of the blades and being of substantially the same Width as the blades, said carrier having the side edges thereof bearing directly against said cutters.

In testimony whereof I affix my signature.

FLOYD S. HARTWELL. 

